Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02792808 2014-02-28
1-1-7535-1-CA
NOZZLE-TIP INSULATOR DEFINING COAXIAL, CONCENTRIC VOID FORMATION
TECHNICAL FIELD
An aspect of the present invention generally relates to (but is not limited
to) a nozzle-tip insulator
having a body defining a void formation that are coaxially concentrically
positioned relative to each
other.
BACKGROUND
The first man-made plastic was invented in Britain in 1851 by Alexander
PARKES. He publicly
demonstrated it at the 1862 International Exhibition in London, calling the
material Parkesine.
Derived from cellulose, Parkesine could be heated, molded, and retain its
shape when cooled. It
was, however, expensive to produce, prone to cracking, and highly flammable.
In 1868, American
inventor John Wesley HYATT developed a plastic material he named Celluloid,
improving on
PARKES' invention so that it could be processed into finished form. HYATT
patented the first
injection molding machine in 1872. It worked like a large hypodermic needle,
using a plunger to
inject plastic through a heated cylinder into a mold. The industry expanded
rapidly in the 1940s
because World War II created a huge demand for inexpensive, mass-produced
products. In 1946,
American inventor James Watson HENDRY built the first screw injection machine.
This machine
also allowed material to be mixed before injection, so that colored or
recycled plastic could be
added to virgin material and mixed thoroughly before being injected. In the
1970s, HENDRY went
on to develop the first gas-assisted injection molding process.
Injection molding machines consist of a material hopper, an injection ram or
screw-type plunger,
and a heating unit. They are also known as presses, they hold the molds in
which the components
are shaped. Presses are rated by tonnage, which expresses the amount of
clamping force that the
machine can exert. This force keeps the mold closed during the injection
process. Tonnage can vary
from less than five tons to 6000 tons, with the higher figures used in
comparatively few
manufacturing operations. The total clamp force needed is determined by the
projected area of the
part being molded. This projected area is multiplied by a clamp force of from
two to eight tons for
each square inch of the projected areas. As a rule of thumb, four or five tons
per square inch can be
used for most products. If the plastic material is very stiff, it will require
more injection pressure to
fill the mold, thus more clamp tonnage to hold the mold closed. The required
force can also be
determined by the material used and the size of the part, larger parts require
higher clamping force.
With Injection Molding, granular plastic is fed by gravity from a hopper into
a heated barrel. As the
CA 02792808 2014-02-28
H-7535-1-CA
granules are slowly moved forward by a screw-type plunger, the plastic is
forced into a heated
chamber, where it is melted. As the plunger advances, the melted plastic is
forced through a nozzle
that rests against the mold, allowing it to enter the mold cavity through a
gate and runner system.
The mold remains cold so the plastic solidifies almost as soon as the mold is
filled. Mold assembly
or die are terms used to describe the tooling used to produce plastic parts in
molding. The mold
assembly is used in mass production where thousands of parts are produced.
Molds are typically
constructed from hardened steel, etc. Hot-runner systems are used in molding
systems, along with
mold assemblies, for the manufacture of plastic articles. Usually, hot-runners
systems and mold
assemblies are treated as tools that may be sold and supplied separately from
molding systems.
SUMMARY
The inventors have researched a problem associated with known molding systems
that
inadvertently manufacture bad-quality molded articles or parts. After much
study, the inventors
believe they have arrived at an understanding of the problem and its solution,
which are stated
below, and the inventors believe this understanding is not known to the
public.
According to one aspect, there is provided a nozzle-tip insulator, comprising:
a nozzle-contact
surface; a mold-gate contact surface being offset from the nozzle-contact
surface; and a body
connecting the nozzle-contact surface with the mold-gate contact surface, the
body being resiliently
compressible, the body defining a void, and the body and the void being
coaxially concentrically
positioned relative to each other.
Other aspects and features of the non-limiting embodiments will now become
apparent to those
skilled in the art upon review of the following detailed description of the
non-limiting embodiments
with the accompanying drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
The non-limiting embodiments will be more fully appreciated by reference to
the following detailed
description of the non-limiting embodiments when taken in conjunction with the
accompanying
drawings, in which:
FIGS. 1A and 1B depict schematic representations of a mold-tool assembly (2)
of a molding
machine (1) using a nozzle-tip insulator (100);
2
CA 02792808 2014-02-28
I1-7535-1-CA
FIGS. 2A-8A depict various schematic representations (that is, cross-sectional
views) of the nozzle-
tip insulator (100) of FIG 1; and
FIGS. 2B-8B depicts various schematic representations (that is, perspective
views) of the nozzle-tip
insulator (100) of FIG 1, which correspond with FIGS. 2A-8A, respectively.
The drawings are not necessarily to scale and may be illustrated by phantom
lines, diagrammatic
representations and fragmentary views. In certain instances, details not
necessary for an
understanding of the embodiments (and/or details that render other details
difficult to perceive) may
have been omitted.
DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENT(S)
FIGS. 1A and 1B depicts the schematic representations of the mold-tool
assembly (2) of the
molding machine (1) using the nozzle-tip insulator (100). As depicted in FIG.
1B, the molding
machine (1) generally includes a stationary platen and a movable platen, and
the mold-tool
assembly (2) is supported between the platens. As depicted in FIG. 1B, the
mold-tool assembly (2)
includes (but is not limited to): a stem actuator (4), a manifold assembly
(6), a stem (8), a nozzle
assembly (116), a mold-gate assembly (118), and the nozzle-tip insulator
(100). The mold-tool
assembly (2) (which may also be called a hot-runner system or a runner
system), the molding
machine (1) (such as an injection-molding machine), and the nozzle-tip
insulator (100) all may
include components that are known to persons skilled in the art, and these
known components will
not be described here; these known components are described, at least in part,
in the following
reference books (for example): (i) "Injection Molding Handbook" authored by
OSSWALD/TURNG/GRAMANN (ISBN: 3-446-21669-2), (ii) "Injection Molding Handbook"
authored by ROSATO AND ROSATO (ISBN: 0-412-99381-3), (iii) "Injection Molding
Systems"
3rd Edition authored by JOHANNABER (ISBN 3-446-17733-7) and/or (iv) "Runner
and Gating
Design Handbook" authored by BEAUMONT (ISBN 1-446-22672-9). It will be
appreciated that
for the purposes of this document, the phrase "includes (but is not limited
to)" is equivalent to the
word "comprising". The word "comprising" is a transitional phrase or word that
links the preamble
of a patent claim to the specific elements set forth in the claim which define
what the invention
itself actually is. The transitional phrase acts as a limitation on the claim,
indicating whether a
similar device, method, or composition infringes the patent if the accused
device (etc) contains
more or fewer elements than the claim in the patent. The word "comprising" is
to be treated as an
open transition, which is the broadest form of transition, as it does not
limit the preamble to
whatever elements are identified in the claim.
3
CA 02792808 2014-02-28
H-7535-1-CA
Referring now to FIGS. 2A and 2B, there is depicted an example of the nozzle-
tip insulator (100).
Generally, the nozzle-tip insulator (100) includes (but is not limited to):
(i) a nozzle-contact surface
(102), (ii) a mold-gate contact surface (104), and (iii) a body (106). The
nozzle-contact surface
(102) is used to contact a nozzle assembly (116). The mold-gate contact
surface (104) is offset from
the nozzle-contact surface (102). The mold-gate contact surface (104) is used
to contact a mold-gate
assembly (118). The body (106) connects the nozzle-contact surface (102) with
the mold-gate
contact surface (104). The body (106) is resiliently compressible. The body
(106) defines a void
formation (108). The body (106) and the void formation (108) are coaxially
concentrically
positioned relative to each other. The void formation (108) permits the body
(106) to uniformly
resiliently compress in response to transmission of a load (110) from the
nozzle-contact surface
(102) to the mold-gate contact surface (104). It is understood that the void
formation (108) reduces
transmission of the load (110) from the nozzle-contact surface (102) to the
mold-gate contact
surface (104). Specifically, the void formation reduces the load (110) being
transmitted from the
nozzle-contact surface (102) to the mold-gate surface (104). The body (106)
defines a (centrally-
located) orifice (120), which allows melt or resin or molding material to flow
from the nozzle
assembly (116) to the mold-gate assembly (118) and ultimately to a mold cavity
of a mold assembly
(known, not depicted). The meaning of "resilience" is as follows: the physical
property of a
material that can return to its original shape or position after deformation
that does not exceed its
elastic limit. The meaning of "compressible" is as follows: an object that is
capable of being
compressed or made more compact; the property of being able to occupy less
space. The meaning
of "concentric" is as follows: having or sharing a common center; concentric
objects share the same
center, axis or origin with one inside the other. Concentric objects do not
necessarily have the same
radius. The meaning of "coaxially" is as follows: objects that may have or
share a common central
axis; objects that each have their own central axis but these axes are
parallel to each other. The
meaning of "uniformly" is as follows: the same throughout or distributed
evenly through an object.
FIGS. 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B depict the case where the nozzle-tip
insulator (100) is
adapted so that the void formation (108) includes an annulus-shaped gap (112)
that is formed by the
body (106).
FIGS. 2A, 2B, 3A, 3B depict the case where the nozzle-tip insulator (100) is
adapted to that the
annulus-shaped gap (112) is formed on the mold-gate contact surface (104). The
annulus-shaped gap
(112) may be called a concentric groove (or a set of concentric grooves).
FIGS. 2A, 2B depict the annulus-shaped gap (112) formed on an outside conical
surface, which is
4
CA 02792808 2014-02-28
H-7535-1-CA
called the mold-gate contact surface (104), of the nozzle-tip insulator (100).
It will be appreciated
that the annulus-shaped gap (112) may also be formed on the mold-gate contact
surface (104). It will
also be appreciated that the annulus-shaped gap (112) may also be formed on
the mold-gate contact
surface (104) and the nozzle-contact surface (102). The mold-gate contact
surface (104) is tapered.
For FIGS. 2A, 2B, the objective is to decrease the surface contact on the mold-
gate contact surface
(104) of the nozzle-tip insulator (100) by providing a relief on the mold-gate
contact surface (104) by
which contact with mold-gate assembly (118) to the nozzle-tip insulator (100)
may be reduced on the
mold-gate contact surface (104). Surface to surface contact is limited to non-
relieved surfaces where
more of the load (110) will be acting thereon. Hence this arrangement may
reduce an amount of the
load (110) acting on the nozzle-tip insulator (100) and in turn the mold-gate
contact surface (104).
FIGS. 3A and 3B depict the case where the void formation (108) includes two
gaps (112) formed on
the mold-gate contact surface (104), in which one of the gaps (112) is formed
closer to the orifice
(120) while the other gap (112) is formed proximate midway between the orifice
(120) and the
5 peripheral edge of the nozzle-tip insulator (100). The gaps (112) form a
corrugated tapered surface
on the mold-gate contact surface (104). For this arrangement, the objective is
to decrease the surface
contact on the mold-gate contact surface (104) of the nozzle-tip insulator
(100) by making a
corrugated surface on the mold-gate contact surface (104) of the nozzle-tip
insulator (100) there may
be a crest and trough, which as a relief on the mold-gate contact surface
(104) by which contact with
the mold-gate assembly (118) and the nozzle-tip insulator (100) may be
reduced. Hence this
arrangement may reduce the load acting on the nozzle-tip insulator (100) and
in turn the mold-gate
assembly (118).
FIGS. 4A, 4B, 5A, 5B depict the case where the nozzle-tip insulator (100) is
further adapted so that
the annulus-shaped gap (112) is formed on the nozzle-contact surface (102).
FIGS. 4A, 4B depict the nozzle-tip insulator (100) arranged with the objective
of decreasing the
surface contact on the nozzle-contact surface (102), which is tapered, by
providing a relief formed on
the nozzle-contact surface (102) by which contact with the nozzle assembly
(116) to the nozzle-tip
insulator (100) via the nozzle-contact surface (102) may be reduced. Surface
to surface contact is
limited in this case to on non-relieved surfaces where more load may act
thereon. Hence this
arrangement may reduce the load acting on the nozzle-tip insulator (100) and
in turn the mold-gate
assembly (118).
FIGS. 5A and 5B depict the concentrically-placed annular gaps (112) on the
nozzle-contact surface
(102), which form a corrugated tapered relief on the nozzle-contact surface
(102). In this case, the
5
CA 02792808 2014-02-28
H-7535-1-CA
objective is to decrease the surface contact on the nozzle-contact surface
(102) of the nozzle-tip
insulator (100) by making or forming a corrugated relief on the nozzle-contact
surface (102). There
may be a crest-and-trough relief. The relief is formed on the nozzle-contact
surface (102) by which
contact with the nozzle assembly (116) to the nozzle-tip insulator (100) may
be reduced. Hence this
arrangement may reduce the load acting on the nozzle-tip insulator (100).
FIGS. 6A, 6B depict the case where the void formation (108) includes a pattern
of pass-through holes
(114) that are formed by the body (106). The pattern of pass-through holes
(114) may be axially-
aligned through holes (that is, axially aligned with the orifice (120), or the
pattern of pass-through
to holes (114) may be aligned perpendicular to the nozzle-contact surface
(102) or the mold-gate
contact surface (104). The pattern of pass-through holes (114) are a
collection of blind holes and/or
through holes that are evenly distributed around the orifice (120) with their
axes parallel to the axis
of the orifice (120). Preferably, the pattern of pass-through holes (114)
extends from the nozzle-
contact surface (102) to the mold-gate contact surface (104).
FIGS. 7A, 7B depict the case where the void formation (108) is defined between
the body (106) and
a nozzle assembly (116). Specifically, the nozzle-contact surface (102)
contacts the nozzle assembly
(116) at an inner peripheral edge of an orifice (120) centrally defined
through the body (106), so that
the void formation (108) is defined between the body (106) and a nozzle
assembly (116). Different
angles on the nozzle-contact surface (102) and/or the mold-gate contact
surface (104) are different
from the corresponding adjacent mating part's surface angle. This arrangement
calls for increased
(internal) included angle. In this case, the objective is to decrease the
surface contact on the nozzle-
contact surface (102) by increasing the internal included angle of the nozzle-
tip insulator (100),
which makes point contact with the nozzle assembly (116) proximate to the
orifice (120). Hence this
arrangement may reduce the load acting on the nozzle-tip insulator (100) and
in turn the mold-gate
assembly (118).
FIGS. 8A, 8B depict the case where the void formation (108) is defined between
the body (106) and
a mold-gate assembly (118). Specifically, the mold-gate contact surface (104)
contacts the mold-gate
assembly (118) at an outer peripheral edge of an orifice (120) centrally
defined through the body
(106), and the void formation (108) is defined between the body (106) and mold-
gate assembly
(118). This arrangement calls for an increased included angle on the mold-gate
contact surface (104);
it will be appreciated that the increased included angle may be arranged on
both the nozzle-contact
surface (102) and the mold-gate contact surface (104). For this arrangement,
the objective is to
decrease the entire surface contact on the nozzle-contact surface (102) and/or
the mold-gate contact
surface (104) by increasing the included angles (both internal and external)
of the nozzle-tip insulator
6
CA 02792808 2014-02-28
H-7535-1-CA
(100), which makes less contact with the nozzle assembly (116) and the mold-
gate assembly (118).
Hence this may reduce the load acting on the nozzle-tip insulator (100) and in
turn the mold-gate
assembly (118).
Several technical effects may be realized by using the foregoing arrangements:
the stiffness of the
nozzle-tip insulator (100) may be controlled by adjusting the geometry of the
grooves, and/or
adding grooves on the nozzle-contact surface (102) and the mold-gate contact
surface (104) and
thus control axial reaction forces that the nozzle-tip insulator (100) may
transmit to the mold-gate
assembly (118), thereby reducing the wear to the mold-gate assembly (118) and
to the nozzle
to assembly (116). In addition, less force transmitted through the mold-
tool assembly (2) may reduce
plate bowing. The arrangement described above may reduce the force transmitted
to the mold-gate
assembly (118), and so by forming grooves in the nozzle-contact surface (102)
and the mold-gate
contact surface (104) of the nozzle-tip insulator (100), the nozzle-tip
insulator (100) may become
less stiff and therefore require less force to compress the nozzle-tip
insulator (100) by the same
compression distance.
It is understood that the scope of the present invention is limited to the
scope provided by the
independent claims, and it is also understood that the scope of the present
invention is not limited
to: (i) the dependent claims, (ii) the detailed description of the non-
limiting embodiments, (iii) the
summary, (iv) the abstract, and/or (v) description provided outside of this
document (that is, outside
of the instant application as filed, as prosecuted, and/or as granted). It is
understood, for the
purposes of this document, the phrase "includes (but is not limited to)" is
equivalent to the word
"comprising". The word "comprising" is a transitional phrase or word that
links the preamble of a
patent claim to the specific elements set forth in the claim which define what
the invention itself
actually is. The transitional phrase acts as a limitation on the claim,
indicating whether a similar
device, method, or composition infringes the patent if the accused device
(etc) contains more or
fewer elements than the claim in the patent. The word "comprising" is to be
treated as an open
transition, which is the broadest form of transition, as it does not limit the
preamble to whatever
elements are identified in the claim. It is noted that the foregoing has
outlined the non-limiting
embodiments. Thus, although the description is made for particular non-
limiting embodiments, the
scope of the present invention is suitable and applicable to other
arrangements and applications.
Modifications to the non-limiting embodiments can be effected without
departing from the scope of
the independent claims. It is understood that the non-limiting embodiments are
merely illustrative.
7
